Differences of the TTL value in Tracert and Ping

networkingpingttl

When I ping localhost on my Windows XP system, the TTL value returned is 128 and it shows me that the default TTL value in the ping for my system is 128.
Then when I ping google.com the returned TTL value is 45, and I assume it means that (128 – 45) / 2 hops are existed in my way to google.
When I tracert google.com, it says that the packets goes for maximum 30 numbers of hops, but it reaches the destination.

Why does it happen? Is it any difference between the TTL value showed in ping and the TTL value of tracert ?!

Thanks in advance . . .

Best Answer

Why does it happen?

Some host in path filtering you traceroute

Is it any difference between the TTL value showed in ping and the TTL value of tracert ?!

no difference(ping ttl=55, tracepath ttl=back=55)... no host filtering trace

ping ya.ru
PING ya.ru (87.250.250.3) 56(84) bytes of data.
64 bytes from www.yandex.ru (87.250.250.3): icmp_seq=1 ttl=55 time=36.6 ms

 tracepath ya.ru

 ....................

 8:  l3-s550-s450.yandex.net (213.180.213.23)              97.070ms 
 9:  l3-s650-s550.yandex.net (213.180.213.29)              97.992ms 
10:  www.yandex.ru (77.88.21.3)                            91.306ms reached
     Resume: pmtu 1500 hops 10 back 55

Then when I ping google.com the returned TTL value is 45, and I assume it means that (128 - 45) / 2 hops are existed in my way to google.

No. Path = 64(default google.com ttl) - 45(ping ttl) = 19 hops

Related Solutions

Why does tracert only report one hop on failure

Well I managed to pinpoint where the error was occurring and it turns out that peerguardian was assassinating all incoming packets to the host. I'm not exactly sure why the tracert looks like it does but it does explain why tracert was never getting any information.

Router – How network devices affect TTL

TTL is part of the IPv4 protocol (on v6 it is called "Hop Limit", as per Steven Monday's comment). Switches and hubs operate on a different layer of the ISO/OSI model (layer 2 as opposed to layer 3 - there do exist so-called layer 3 switches, but I assume you're not asking about them as you include hubs as well).

The TTL field is set by the sender of the datagram, 
and reduced by every host on the route to its destination.

http://en.wikipedia.org/wiki/Time_to_live

A switch or hub isn't a host on the IP protocol sense - they usually don't have IP addresses. If they do (in the case of switches) they are for management purposes and don't really take part in the actual functioning of the device. Switches work with MAC addresses instead, mapping them to ports and "routing" the packet only in the sense of sending it down the right port (hubs do much less work and send them through all ports instead). They don't inspect or alter the IP payload - you could be using other protocols as well.

http://en.wikipedia.org/wiki/ISO_model

Best Answer

Related Solutions

Why does tracert only report one hop on failure

Router – How network devices affect TTL

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